[TF-A] Proposal: TF-A to adopt hand-off blocks (HOBs) for information passing between boot stages

[François Ozog]

On Sat, 10 Jul 2021 at 01:07, Julius Werner <jwerner at chromium.org> wrote:

> > - "bloblist" is a general term for concept of linked list and it's not
> exactly U-boot implementation. The proposed solution will cause some degree
> of changes in all the participating projects. For backward compatibility
> issue, we have already though about it and proposed to have build configs
> which will be enabled by platform integrators.
>
> Okay, let's gather the requirements and then decide how the existing
> system needs to be expanded to meet them. Please keep me in the loop
> on those discussions.
>
> > > U-Boot has an established mechanism which is used in particular on all
> chrome
> > > books in both x86 and Arm environments.  I have the impression that
> > > U-Boot is the typical BL33 so I would import the mechanism into TFA,
> > > not the other way round.
>
> There has been no Chromebook (x86 or Arm) shipping with U-Boot since
> 2013 (before TF-A existed). In fact, Chromebooks are all running
> coreboot today and using the bl_aux_params mechanism (it's 3 SoC
> vendors, more than 3 SoCs, but the parameter code is shared at the
> vendor level), and one of my concerns here is trying to limit
> disruption to those existing setups. I don't have enough data to say
> what the "typical" boot flow among all TF-A devices in existence is,
> but at least for the millions of Chromebooks out there it is coreboot
> + TF-A, not U-Boot.
>
My bad! I candidly inferred from Chromebook reference in U-Boot and Simon's
VBE proposal that U-Boot was used.


-- 
François-Frédéric Ozog | *Director Business Development*
T: +33.67221.6485
francois.ozog at linaro.org | Skype: ffozog